Lower skeletal muscle capillarization and VEGF expression in aged vs. young men

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Abstract
Recently, we observed that muscle capillarization, vascular endothelial growth factor (VEGF) protein, and the VEGF mRNA response to acute exercise were lower in aged compared with young women (Croley AN, Zwetsloot KA, Westerkamp LM, Ryan NA, Pendergast aged men, Hickner RC, Pofahl WE, and Gavin TP. J Appl Physiol 99: 1875–1882, 2005). We hypothesized that similar age-related differences in muscle capillarization and VEGF expression would exist between young and aged men. Skeletal muscle biopsies were obtained from the vastus lateralis before and at 4 h after a submaximal exercise bout for the measurement of morphometry, capillarization, VEGF, KDR, and Flt-1 in seven aged (mean age 65 yr) and eight young (mean age 21 yr) sedentary men. In aged compared with young men, muscle capillary contacts and capillary-to-fiber perimeter exchange index were lower regardless of fiber type. Muscle VEGF mRNA and protein were lower in aged men both at rest and 4 h postexercise. Exercise increased muscle VEGF mRNA and protein and KDR mRNA independent of age group. There were no effects of exercise or age on muscle Flt-1 mRNA or protein or KDR protein. These results confirm that skeletal muscle capillarization and VEGF expression are lower in aged compared with young men.